The proposed sale of Opel to the Canadian supplier, Magna, could have hit a roadblock.

Talks between General Motors and the Canadian auto parts giant, Magna International, appear to be running into snags, threatening the planned sale of a majority stake in GM’s huge and troubled European subsidiary, Opel.

A number of alternatives bidders are now pushing to displace Magna as the preferred partner in an Opel sale, including the Belgian industrial holding company, RHJ International, and China’s Beijing Automotive Industry Corp. The Italian automaker, Fiat, is also reportedly looking for ways to revive its own bid, which lost out to the offer from Magna.

The unexpected turns of events comes precisely one month after the Canadian supplier and its Russian ally, Sberbank, appeared to lock down the purchase of a majority stake in Opel, the German-based GM operation that was teetering perilously close to insolvency. The U.S. automaker was under intense pressure to conclude a deal with one of three final bidders in order to win a $2.5 billion bridge loan from the German government.

But “the initial celebration” was premature, a source close to Opel tells TheDetroitBureau.com. “What was signed was a Memorandum of Understanding (MOU), not a sales agreement. And since then, others have come along.”

An MOU simply puts talks on the fast track between a seller and what, at the time, seems the most likely purchaser. But there are generally no guarantees that the sale will go through, especially if other interested parties, such as RHJ, Beijing Auto or Fiat, either come along or decide to increase their earlier offers.

Prior to signing the MOU with Magna, a deeply-placed GM source told TheDetroitBureau that his company was hoping to have dual-track discussions with at least two potential partners. That, he explained, would allow the struggling U.S. maker – now in Chapter 11 – to extract the best possible deal.

At this point, it appears quite possible a separate memorandum could be signed with RHJ, according to several sources, pitting the Belgian company against Magna in the race to conclude the sale.

The latter company still appears to have the support of Opel’s trade unions, as well as key members of the German government. A well-placed source emphasizes that Berlin is “absolutely key” to any final deal, including the pace at which it is completed. Indeed, he adds, the government might not have even considered a bailout had it not been for the fact that there is a general election coming up. “You don’t want to go into an election being the ones who sank a German icon.”

Whether Magna’s backers carry enough sway to win over GM negotiators is unclear, however. There appear to be several concerns, including the possibility that Sberbank would set up its own plant in Russia, possibly competing with GM, which is investing heavily in that large market.

Insiders say that, longer-term, GM was also hoping to set up a deal in which it would have an opportunity to repurchase at least some of the stake it will give up in Opel. That appears to be something that Magna and Sberbank are resisting.

With the bridge loan in place, GM has a little breathing room to press for a better deal. But just how much longer it can hang on is unclear. Sources say that Berlin will be pressing hard to wrap up the Opel sale before the upcoming German election.